Tape-Drive Silver sails are made with a grid of S-Glass fiber tapes bonded to a sail made with polyester laminates. This combination can be used on boats under 40-feet as a more economical choice. When S-Glass tapes are used on polyester laminates, the sail has an all-white look. (See detail picture). These sails offer vastly better shape holding than a similar Dacron sail and the price increase is surprisingly small.